Chris an sock: Yep, you can monitor the protocol but it's very dificul to know a protocol by looking it through a sniffer (or snifer?
). Also you can copy the asm code but that will cause legal troubles as wtbw said.
Anyway, I know that whatever M$ does, it will be copied by people in more or less time and more or less legally. I think that on Oct 15th (or the day M$ changes its protocol) only M$ clientes would be able to sing in on Messenger service and that's a pain in the ass (mmm... not sure if this last expresion means what I want to say)
/ 
